Herein, in step 1, the intermediate 1-methyl imidazole in tetrahydrofuran, is mixed with a solution of n-butyllithium in a hexane solvent to which is added chlorotriethylsilane (triethylsilyl chloride), followed by a further addition of n-butyllithium in hexane, the resulting mixture being cooled to −78° C. before the addition of a solution of a compound of formula (I), i.e. 6-(4-chlorobenzoyl)-4-(3-chlorophenyl)-1-methyl-2(1H)-quinolinone in tetrahydrofuran. The reaction mixture is subsequently brought to room temperature, and then hydrolysed, extracted with ethyl acetate and the organic layer worked up to obtain a compound of formula (II), i.e. (±)-6-[hydroxy(4-chlorophenyl)(1-methyl-1H-imidazol-5-yl)methyl]-4-(3-chlorophenyl)-1-methyl-2(1H)-quinolinone.
